diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 0dc13bc958..6b84cc48c6 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -773,7 +773,7 @@ int cg_is_empty(const char *controller, const char *path) {
         if (empty_or_root(path))
                 return false;
 
-        r = cg_get_keyed_attribute(SYSTEMD_CGROUP_CONTROLLER, path, "cgroup.events", STRV_MAKE("populated"), &t);
+        r = cg_get_keyed_attribute(controller, path, "cgroup.events", STRV_MAKE("populated"), &t);
         if (r == -ENOENT)
                 return true;
         if (r < 0)
diff --git a/src/test/test-cgroup.c b/src/test/test-cgroup.c
index 77f720fd2d..d32b119d26 100644
--- a/src/test/test-cgroup.c
+++ b/src/test/test-cgroup.c
@@ -103,6 +103,8 @@ TEST(cg_create) {
 
         ASSERT_OK_POSITIVE(cg_is_empty(SYSTEMD_CGROUP_CONTROLLER, test_a));
         ASSERT_OK_ZERO(cg_is_empty(SYSTEMD_CGROUP_CONTROLLER, test_b));
+        ASSERT_OK_POSITIVE(cg_is_empty(NULL, test_a));
+        ASSERT_OK_POSITIVE(cg_is_empty(NULL, test_b));
 
         ASSERT_OK_ZERO(cg_kill_recursive(test_a, 0, 0, NULL, NULL, NULL));
         ASSERT_OK_POSITIVE(cg_kill_recursive(test_b, 0, 0, NULL, NULL, NULL));